Showing papers by "Vaughn College of Aeronautics and Technology published in 1977"

The use of wing tip sails to reduce vortex drag

Abstract: Windtunnel measurements of the flow around the tip tanks of a model of a Morane-Soulnier Paris aircraft have been used to design cambered and twisted auxiliary surfaces, each only 0.4% to 0.6% of the wing area, which unwound the tip vortices formed at incidence and in so doing experienced a thrust, effectively reducing the vortex drag. Flight tests on a Paris aircraft showed that three such sails per tip tank increased the effective aspect ratio of the wing by over 40%. The increase in the overall lift-drag ratio at a lift coefficient of 0.35 was 21% and the maximum lift-drag ratio increased from 12.5 to 15.8. More recent windtunnel tests have shown that sails have a similar effect when fitted to plain wing tips. The results suggest that three or four sails spiralled round the rear half of each wing tip will give best results. These encouraging results suggest that far more windtunnel, flight and design work should be done to realise the potential savings in drag and fuel. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.